Manufacture of synthesis gas



1956 P. w. GARBO MANUFACTURE or sm-mssxs GAS Origihal Filed on. 2. 1946 WWETITB R. PAUL W GAReo AT TORNE Y United States Patent ()fice Matterenclosedinbeavy brackets appearsintlie P New York, N. Y., a corporation of orlglnal patent but forms nopart ofthis reissue specifi-- cation; matter printed in italics indicates the additions nude by rehsue.

N. Y., or to Hydrocarbon The present invention relates to high temperature exothermic reactions and is more particularly concerned with the interaction of a hydrocarbon and an oxygencontaining reactant with partial combustion for production of mixtures comprising essentiallyv hydrogen and carbon monoxide known in the art as synthesis gas.

While the invention, for purposes of convenience in illustration, will be described more particularly in connection 'with the preparation of synthesis gas from hydrocarbons,

nevertheless it will be understood that the principles thereof are equally applicable to equivalent exothermic processes, particularly where relatively high temperatures are desirably maintained in the reaction zone.

In the co-pending application Serial No. 700,019, filed September 28, 1946 in. the name of Percival C. Keith, which matured as U. S. Patent No. 2,642,346 on June 16, 1953, there is disclosed a process and apparatus for the preparation of synthesis gas in the presence of a granular heat absorptive material (hereinafter referred to as a thermophore) whichjabsorbs the heat of reaction in the zone of heat liberation and is later passed countercurrently to incoming feed gases in 'order to transfer its sensible heat to the feed gases. Operating in this manner, it is possible to supply reactants to thereaction zone at such a temperature that relatively high reaction temperatures of 2000 F., or materially thereabove, can be maintained. In accordance with that disclosure, the granular heat absorbing material may be inert or may comprise or include a catalyst \for the reaction in question, and it is disclosed that split streams of the heated solid may be employed to preheat the respective reactant gases individually. By this means, intermixing of the reactants is avoided in advance of the combustion zone, and the serious problems ofpreheating explosive mixtures are obviated.

This method of operation has the disadvantage that hydrocarbon feeds, preheated to high temperatures, are subject to thermal decomposition with the production of undesirable by-products, including carbonaceous material which tends to deposit upon and foul the thermophore. 0n the other hand, the aforesaid application contemplates overcoming this difliculty by recirculating the thermophore through the system in such a manner that random portions thereof are continuously being diverted to the oxygen preheating zone, wherein carbon is removed by combustion. This, however, tends to introduce variable quantities of carbon dioxide into the gas generation zone and may, under some circumstances, result in an unfavorable heat distribution with excessive heat energy being liberated in the preheating of oxygen.

It is an object of the present invention to overcome the disadvantages of the foregoing procedure by providing a process wherein the preheating of the hydrocarbon feed is restricted to a temperature range within which decomposition is substantially avoided while supplying the heat h 2 energy to the incoming stream of oxygen or oxygen-com taining reactant at a higher temperature level approaching that of the exothermic reaction zone.

' A further object of the present invention contemplates the initial passage of relativelystable reactant gases in heat exchange relation with the hot thermophore prior to preheating a less stable reactant feed, whereby the thermophore reaches the less stable reactant at a controlled temperature such that thermal decomposition is avoided. Other and further objectives will be apparent from a consideration of the following disclosure.

In order to more specifically illustrate the invention, reference is had to the figures of the drawing, wherein Figure 1 represents more or less diagrammatically one combination of apparatus suitable for carrying out the present process; Figure 2 illustrates a preferred combination of apparatus; and Figures 3 4 and 5 respectively disclose, only schematically, other suitable embodiments of the invention.

In Figure l, the reference numeral 10 indicates a combustion or reaction vessel provided with an internal refractory lining 11 and containing a body of granular heat absorbing material 12. The granular contents-are supplied through standpipe 13 by means of any suitable mechanical feeding device such as star feeder 14 operated at a predetermined rate. The star feeder l4 and standpipe 13 continuously receive a supply of the heat absorbing particles through the agency of a worm conveyor 15, which in turn is supplied from an elevator .16 indicated only in dotted lines.

The thermophore is continuously discharged from the bottom of the reaction chamber 10 through outlet standpipe 17 controlled by star feeder 18 operating in coordination with the star feeder 14. Standpipe 17 discharges directly into preheating chamber or zone 19, similarly advantageously provided with a refractory lining 20. A further standpipe 21, connecting with the bottom of the preheating chamber 19 and controlled by a third star feeder 22, discharges directly into a second preheating chamber 23, which in most embodiments of the present invention need notbe provided with a refractory lining. The second or lower preheating chamber 23 similarly discharges into standpipe 24 leading by way of feeder 24A to screw conveyor 25 which supplies the aforementioned elevator 16.

With the foregoing combination of feeding and conveying instrumentalities, therefore, the granular thermophore may be passed in a continuous cycle from the lower portion of the second preheating chamber through the elevator to the gas reaction chamber and thence successively through the reaction or combustion zone and the two preheating zones. Under properly coordinated conditions of operation, it will be apparent-that the thermophore level can be maintained substantially constant in each of the three chambers, as, for example, at the level indicated by the reference numeral 26 in chamber 19 and by the reference numeral 27 in chamber 23.

During the progress of such cycle a hydrocarbon gas, such as methane, from any suitable source not shown, is introduced through. inlet pipe 28 to the bottom of preheating chamber 23 and passes upwardly in countercurrent relation to the downcoming thermophore, emerging from its upper surfacev 27 and flowing by way of outlet pipe 29 to the lower portion of the combustion chamber 10. At the same time, oxygen, for example, is introduced from any suitable source, not shown, by way of inlet pipe 30 and similarly moves incountercurrent relation to the thermophore in the preheating chamber 19, collecting in the upper portion thereof above thermophore level 26 and passing by way of pipe 31 to the lower portion of the reaction zone 10. The reaction products evolved are conducted Reissued May 8, 1958 out through 32 for further use, as for to a system operating for the synthesis of hydrocarbons.

. is heated to atemperature In operation, therefore, methane and oxygen, for

' example, mix and react in the chamber heating its content of heat absorbing granules to the desired reaction temperature. Hot. thermophore discharged from the reaction zone gravitates into the vessel 19 at substantially reaction temperature and is progressively cooled to any desired degree by-the countercurrent passage of incoming oxygen. Accordingly, the thermophore leaving the chamber 1! and entering chamber 23 is at a substantially lower temperature level depending upon the quantity of sensible heat energy abstracted by the passage of oxygen. The thermophore is further cooled'to any desired lower level by the countercurrentpassage ofthe methane in the lower chamber 23.

Following thismethod of operation it is obviously while at the same time lowering the temperature of the thermophore supplied to the second preheating ,zone to possible to preheat the oxygen stream toany desired temperature approximating the reaction temperature,

a level favorable for preheating the second reactant without adverse thermal efiects. In short, the invention provides an arrangement whereby a reactant gas, which has substantial or complete thermal stability, is used to ab-' stract sensible heat from the thermophore in advance of preheating a relatively thermally unstable reactant to a predetermined lower temperature forsupply to a reaction Where excess heat energy is available in the system, a heat exchanger 33 may be inserted in any one or more of the three chambers shown. The heat exchanger 33 may take any conventional form, preferably a series of vertically extending tubes joining with headers so configurated as to permit free gravitation of solid particles therealong. lnlet pipe 34 and outletpipe 35 permit circulation of any suitable heat transfer medium such as water, Dowtherm or mercury, and the device may be operated where desired to generate steam for the operation of the mechanical conveying means or for other purposes; Where the high temperature reaction is insutlicien'tly exothermic to compensate for heat losses withdrawn and in a further zone passed in countercurrent relationship to a stream of natural-gas introduced at atmospheric temperature and discharged at about 800' F. The natural gas stream comprising about 75% methane, 13% higher hydrocarbons and 10% hydrogen,

is introduced at the rate of'about 3900 cubic feet per hour. The respective streams 'of natural gas and oxygen are admixed in the reactor and proceed to react at the foregoing reactor temperature with the production of a gas containing, after removal of water of reaction, about 2% nitrogen, about 2% methane, and about 5% carbon dioxide, the remainder being hydrogen and carbon monoxide in the molar ratio of 2: l. The rate of thermo- 'phore circulation is readily adjusted to maintain the foregoing temperatures in the respective zones. Thus, when operating-as above, the thermophore is discharged from the lower preheating zone to the elevator at a temperature of, about 200 F. and returned to the reaction' zone.

It is important to point out that. the present invention is not limited to operation with a packed generator, but, as is indicated in Figure 2, may function with a generator having an open gas generation chamber provided the sensible heat from the products of combustion is transferred to the circulating thermophore. Referring more specifically to this figure, the gaseous reactants are preheated in a chamber 36 provided with a refractory lining 31, through which the thermophore continuously gravitates as before. .The oxygen stream, for example, in troduced by way of inlet pipe 38 passes upwardly in countercurrent relationship through the hot thermophore,

. and is withdrawn to the lower portion of the generator from the system, exchanger 33 may be operated to supply heat in amount to balance the losses.

Any conventional means may be employed for assuring the introduction of the preheated feed gases into the reaction zone in good admixture. Thus, pipes 29 and 31 advantageously discharge into-the reactor in opposed relationship. Alternatively, however, the two streams of' I gas may be introduced through any conventional type of mixing nozzle so that they reach the interior of the zone in condition for immediate reaction. The reaction products pass upwardly through the thermophore in countercurrent heat exchange relationship and are carried off through outlet quired.

From the foregoing, it will be apparent that the present conduit 32 for use or disposition as reinvention is particularly advantageous in the manufacture ofsynthesis gas for the production of hydrocarbons and oxygenated hydrocarbons by the'catalytic reduction of,

carbon monoxide by hydrogen. Thus, with a reactant feed approximating 1 mol of oxygen for each 2 mols of methane, for example, and a temperature of 2100 F. and upwardly in the reaction chamberltl, the reaction gases will consist essentially of hydrogen and carbon monoxide in the molar ratio of about 2:1. With proper control of temperatures and proportions of reactant feedand by the use of substantially pure oxygen, the reaction product, freed of reaction water, may contain as much as 85% -or more of the two desired gases, the remainder being essentially nitrogen, carbon dioxide and methane. In accordance with one specific example of the process, a stream of circulating thermophore, in a system analogous to that described in connection with Figure 1, passes through a reaction zone in which the thermophore 43 by pipe 39. In the present embodiment, the hydrocarbon gas is supplied by way of inlet pipe 40 through a heat exchange coil 41 disposed within the downflowing mass of thermphore. In short, the methane in this embodiment passes in indirect counter-current heat exchange relationship with the thermophore and at the predeter-.

. mined temperature of preheat is discharged through outlet pipe 42 to the generator 43.

In this instance, the generator 43 comprises a chamber having arefractory lining 44 and an upper outlet conduit 45. It is advantageously free from granular packing of any kind, so that the gases react in an open, unpacked space. More specifically, in order to inhibit production of free carbon, I prefer to maintain the ratio of internal generator surface [,1 to generator volume at as low a value as possible, i. e., as low as is practicable from an engineering viewpoint. ratio of internal surface to volume in the generator or reaction zone is less than I the surface area and volume being computed in terms of feet as the linear unit of of measurement. As illustrated by the generally cylindrlcal generator 43 of Figure 2, the proper configuration of the generator is one which avoids extensive or'excesslve surface, i. e., the generator for any given volume is chosen to have a low ratio of internal surface to volume.

Reaction products, essentially hydrogen and carbon monoxide, pass by way way of conduit 45 into the lower portion of a heat transfer chamber or accumulator 46, wherein they pass upwardly in countercurrent relationship with the content of granular thermophore, heating it to a temperature closely approximating reaction temperature the vicinity of the discharge standpipc 54.

Advantageously, the

. phore from the bottom of the preheating chamber 86,

a screw conveyor 49 supplying an elevator represented only by the dotted line 59, and a receiving screw conveyor 51 at the top of the elevator. The screw conveyor 51 continuously supplies thermophore to a standpipeSZ controlled by star feeder 53 and supplying the accumuator chamber '46. The solid granules pass out of the accumulator by way of standpipe 54 controlled by star feeder 85 and are received in the lower or preheating chamber 36. As before, the mechanical means are so operated as to maintain the indicated levels of granular thermophore in the respective chambers.

In 1 operation of this device, it will be apparent that the preheated oxygen reaches the generator at approximatelyv reaction temperature, whereas the hydrocarbon gas is supplied at a somewhat lower temperature favorable, in the aggregate, to a good overall heat energy utilization.

Referring to Figure 3, there is indicated schematically a further modified embodiment of the invention, wherein the thermophore circulates continuously thru a closed cyclic path including two vertically disposed chambers or vessels 60 and 61 and an elevator system represented by the dotted line 62. The upper vessel 60 is fed with thermophore at its upper end, thru inlet standpipe 63, controlled by star feeder 64. Standpipe 65 and star feeder 66 convey the thermophore from vessel 60 to vessel 61, and the lower standpipe 67 and feeder 68 discharge into the elevator for return to the vessel 60.

The relatively heat unstable reactant, as for example methane, is passed into the lower portion of vessel 61 thru inlet pipe 69 and distributing head 70, passing upwardly in direct countercurrent exchange with the thermophore, and leaving vessel 61 via pipe 71, in the preheated condition. Pipe 71 feeds the preheated reactant into vessel 60 via distributing head 72' spaced vertically above the lower extremity thereof.

The relatively heat stable reactant, as for example oxygen, is preheated in the portion of vessel 60 below the distributor 72 by introducing it thru inlet 73. Prodnets of reaction are withdrawn thru outlet pipe 74.

In this embodiment the two reactants meet, intermingle and react in a section of the vessel just above the inlet 72, indicated approximately by the bracket A. Above this reaction zone the fluid products of reaction rise in direct countercurrent contact with the downcoming thermophore and are cooled while heating the thermophore to the region of reaction temperature. Accordingly, the thermophore is successively heated by reaction products, passed thru the reaction zone, and thereafter passed first, in direct heat exchange relation with the incoming, relatively heat stable reactant and thereafter, with the relatively heat unstable reactant.

In the embodiment of Figure 4 a single vessel 76 is continuously supplied with a downwardly gravitating mass of thermophore circulated via the elevator 62 and feeders '64 and 68. The relatively heat stable reactant is in troduced at a low point in the vessel thru inlet 77, whereas the heat unstable reactant passes thru inlet 78'and in-v direct heat exchanger 79. The heat exchanger 79 may 6 tially contacts the downcoming hot thermophore and is heated to a highertemperature level than the relatively heat unstable reactant, while cooling-the thermophore to reduce it to an appropriately lower temperature level. This preheating space may be occupied by a second heat exchanger 82 supplied with a suitable heat transfer fluid via inlet 83 and outlet 84. By this means heat energy may be added to or withdrawn from the system.-

For example, a coolant may be circulated, where required, to maintain the temperature of preheating in the exchanger 79 below a safe maximum limit.

Pursuant to this arrangement, preheating of reactants occurs in the zone below inlet 81, the less stable reactant receiving its preheatin the lower section of the zone after predetermined cooling of the hot thermophore has been efiected. Reaction is completed in the zone A, and thereabove the reaction product gases are cooled to any desired degree by exchange with the stream of thermophore,

take any conventional form, as for example, a series of tubes joined by headers past which the thermophore is free to gravitate. The hot thermophore passing the tubes indirectly heats the internal stream of reactant which is withdrawn thru outlet 80 and returned to the interior of the vessel 76 via distributing head 81.

It is to be noted that the inlet 81 is disposed asubstantial distanceabove the heat exchanger 79 so that the other reactant traverses a substantial path where it inibeing withdrawn as at 85. y

In the embodiment of Figure 5, reaction occurs in the vessel 86 just above distributing inlet 87 for the less stable reactant. The thermophore circulates downwardly and at the base of the vessel 86 is split into two streams by branch standpipes 88 and. Standpipe 88 passes directly into preheating vessel 90 whereas standpipe 89 discharges thru star feeder 91 into preheating vessel 92. .The two preheating vessels inv turn discharge thru standpipes 93 annd 94 andfceders 95 and 96 into the conveyor and elevating system 62 for return to the top of vessel 86 via standpipe 97 and feeder 98.

Methane, for instance, is supplied to preheating vessel 92 thru distributing inlet 99, passed upwardly thru the hot thermophore and, at the selected level of preheat, conducted to inlet 87 via the pipe 100. Oxygen, on the other hand, is concurrently fed into the lower portion of vessel 90 thru distributing inlet 101 and passes upwardly and successively thru that vessel, the standpipe 88 and the lower section of vessel 86.

Above the inlet 87 the two reactants meet and react in the zone A. The relatively more stable reactant, oxygen in the above illustration, is preheated by direct 'countercurren-t exchange with the thermophore in the vessel 90, the standpipe 88 and the vessel 86, the last stage of preheating serving to cool the hot thermophore to any selected level suitable for contact with the reactant in vessel 92. Obviously by suitable relative proportioning of the thermophore streams in vessels 90 and 92, and by properly proportioning thelower preheating zone of vessel 86, the preheating in vessel 92 may be controlled within narrow limits. A heavy exchanger may be incorporated in the lower portion of vessel 86 if additional control is required.

While mention has been made of oxygen as one of the reactants, it is to be understood that this refers only to a preferred embodiment submitted for illustrative purposes. In place of oxygen, various oxygen-containing gases such as air may be supplied.

As is known, moreover, the oxygen compounds such as carbon dioxide and/or water vapor may be used in addition to oxygen. Frequently, as much as 20 or 30% of carbon dioxide and/or water vapor may be employed along with oxygen without lowering the reaction temperature below that required for optimum operation. use of carbon dioxide or steam is of advantage in permitting adjustment of the relative proportions of hydrogen and carbon monoxide in the synthesis gas produced. I

The invention is of advantage in obviating the normal detrimental effects of high temperature oxygen upon heat exchangers or other instrumentalities with which it comes in contact. Thus, it will be noted that, in accordance with the present invention, the high temperature oxygen contacts only relatively inert thermophore or the relatively inert refractory lining of the preheating vessel, and is discharged directly into the genera- The I 7 I tor, but for the interconnecting pipes or conduits which may be adequately protected. I

With reference to the temperatures ofpreheat, methane may normally be heated to temperatures as high as 900' F. without material It 'willbe apparent from the foregoing, that the invention, however, is applicable to other hydrocarbons each having,

phore circulation should be so adjusted that the heat extracted by the oxygen or oxygen-containing gas is suflicient to reduce the thermophore temperature to the appropriate level required in the preheating of the hydrocarbon.

It is to be understood that many granular heat absorptive solid materials are suitable. Necessarily, this solid possesses refractory characteristics enabling it to maintain its discrete solid condition at temperatures which may desirably range above 1800' F. and as high as 3000' F. or thereabove. By way of example, suitable materials are magnesia, zirconia, thoria, alundum, carborundum, temperature resistant alloys and many othshiptosaidmassofsolidheatcarrierbodiesinsuch order that the oxygen-containing reactant initially meets said mass-of solid heat carrier bodies and substantially.

lowers its temperature, and thereafter the hydrocarbon reactant is passed in heat exchange relationship and'preheated to a relatively lower temperature.

" 2. The method as' defined in claim 1, wherein the reaction zone is on vopen, unpacked space which is free ing zone at a temperature below about 1000' F. and

wherein the.hydrocarbon is thereafter preheated to a ers. So, also, it may be advantageous in many instances to substitute for the inert thermophore a catalyst for. the reaction in question or to employ an inert thermophor'e having such a catalyst, as nickel, thereon. The thermophore particles should be of a size such that they are easily handled in apparatus of the type contemplated. Furthermore, the particles should be of such size and shape that gases and vapors can flow up through. a bed thereof without large pressure drops. Generally, it is advisable to employ fairly uniform-sized particles .not smaller than, say, 40 mesh material. Pref .heat carrier bodies in such order that the oxygen-con- I taining gas initially meets the solid heat carrier bodies and substantially lowers their temperature, and therelyst at pressures of 200 to 250 lbs. per sq. in. gauge, it

is advisable to operate the process of the present invention at the same elevated pressure to produce the synthesis. gas. I I

Many other specific modifications and adaptations of the present inventionwill be, obvious to those skilled in theart from a consideration of the foregoing more or less exemplary disclosure and it is therefore understood the invention is not limited to any such details except as defined by the following claims.

I claim:

1. In the high temperature manufacture of synthesis gas composed essentially of hydrogen and carbon monoxide by the reaction of reactants comprising a hydrocarbon and an oxygen-containing gas, the steps which comprise supplyingsaid reactants to a reaction zone operating at reaction temperature, and in relative quantities operative for the production of a reaction product containing essentially carbon monoxide and hydrogen, transferring heat energy from the reaction zone to a mass of solid, granular teat carrier bodies, and continuously and individually p:eheating said reactants by separate passage in countercurrent heat exchange relationfrom granular packing and has a low ratio of internal surface to volume, said ratio being less than I when 'said surface and said volume are computed in terms of mass of heat carrier bodies in a heat'tr'ansfer zone separate from said reaction zone.

3:2 The method as defined in claim 1, wherein the solid heat carrier bodies leave the oxygen preheattemperature below about 1000' F.

413]. In the high temperature manufacture of synthesis gas composed essentially of hydrogen and carbon monoxide by the reaction of reactants comprising a hydrocarbon and an oxygen-containing gas, the steps which comprise supplying said reactants to a reaction zone operating at reaction temperature, and in relative quantities operative for the production of a reaction product containing essentially carbon monoxide and hydrogen, transferring heat energy from. the reaction zone to a mass of solid heat carrier bodies, and continuously and individuallypreheating said reactants by separate passage in heat exchange relationship to said solid after the hydrocarbon reactant is passed in heat exchange relationship and preheated without substantial decomposition. I

5[4]. In thehigh temperature manufacture of synthesis gas composed essentially of hydrogen and carbon monoxide by the reaction of reactants comprising a hydrocarbon and an oxygen-containing gas, the steps which comprise supplying said reactants to a reaction zone operating at reaction temperature, and in relative quantities operative for the production of a reaction product containing essentially carbon monoxide and hydrogen at said high temperature, transferring heat energy from said high temperature reaction product to a massof solid heat carrier bodies to raise the temperature thereof, continually passing. said hot solid heat carrier bodies through first and second preheating zones in succession and then returning them into heat transfer relationship with hot reaction product, and continually and individually preheating said reactants by separate passagein heat exchange relationship to said solid heat carrier bodies in such order that'the oxygen-containing gas initially meets the solid heat carrier bodies in the first preheating zone and substantially lowers the temperature thereof, and thereafter, the hydrocarbon reactant is passed in heat exchange relationship in the succeeding preheatingzone and preheated 'without substantial decomposition.

6[5]. The memes according to claim 5E4] where- 8. The method according to claim 6 wherein the reaction zone is an open, unpacked space which is free from granular packing and has a low ratio of internal surface to volume, said ratio being less than I when said surface and saidvvolume are computed in terms of feet as the linear unit of measurement, whereby to in-' hibit the production of free carbon.

9B]. The method according to claim [4] wherein said oxygen-containing gas is composed of high purity 1m]. In the high temperature manufacture of synthesis gas composed essentially of hydrogen and carbon monoxide by-the reaction of reactants comprising a hydrocarbon and an oxygen-containing gas, the steps which comprise supplying said reactants to a reaction zone operating at reaction temperature, and in relative quantities operative for the production of a reaction product containing essentially carbon monoxide and hy-.

drogen, continuously feeding a stream of solid heat carrier bodies to said reaction zone, transferring heat energy from the reaction zone to said solid heat carrier bodies to substantially raise the temperature thereof, withdrawing hot solid heat carrier bodies from the reaction zone, and continuously and individually preheating said reactants by separate passage in heat exchange relationship to said solid heat carrier bodies in suchorder that and individually preheating saidneactants by separate passage in countencurrent heat exchange relationship to said solid heat carrier bodies in such order that the relatively heat-stable fluid initially meets the solid heat carrier bodies and substantially lowers their temperature, and thereafter, the relatively heat-unstable re-v actant is passed in heat exchange relationship and preheated without substantial decomposition.

12. In the high temperature manufacture of synthesis gas composed essentially of hydrogen and carbon monoxide by the reaction of reactants comprising a hydrocarbon and an oxygen-containing gas, the steps which comprise separately preheating said reactants, supplying the preheated reactants to an open, unpacked reaction zone free from granular packing and having a low ratioof internal surface to volume, said ratio being less than 1 when said surface and said volume are computed relative quantities for production of the desired product, transferring heat energy from the reaction zone to a mass of solid heat carrier bodies, and continuously in terms of feet as the linear unit of measurement, where- 'by to inhibit the production of free carbon, said preheated reactants being supplied in relative quantities operative for the production of a reaction product containing essentially carbon monoxide and hydrogen, and maintaining said reaction zone at a temperature of at least 2100 F. and a pressure of a least 200 lbs. per sq. in. gauge.

'13. The method according to claim 12 wherein the hydrocarbon is'natural gas and the oxygen-containing gas is high purity oxygen.

ltalereneelchsdintlaefileotthispatent ongtnalpatent UNITED STATE PATENTS 1,738,890 Goodrich Dec. 10, 1929 1,904,153 Lucke Apr. 18, 1933 1,966,610 Chilowsky July 17, 1934 2,399,450 Ramseye'r Apr. 30, 1946 2,582,938 Eastman et a1. Ian. 15, 1952 cm am ,oNi

It; 15 hereby certified appeare the printed specification 1.91 abovegmmberedi patent requiring correction and that the said-Letters Patent as corrected below. 4 v

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' 091mm 8', ,11n75; jclaic'refeience dimer-a1 "6" in' ita'i'iee I cooled 1956.

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